V. Heyer et al., A fracture criterion for conducting cracks in homogeneously poled piezoelectric PZT-PIC 151 ceramics, ACT MATER, 46(18), 1998, pp. 6615-6622
A fracture criterion For conducting cracks in piezoelectric ceramics under
combined electrical and mechanical loads is proposed in connection with a m
easured material specific fracture curve of PZT-PIC 151. The characteristic
fracture curve of the investigated material is a function of the stress in
tensity factor, K-I, which is known from fracture mechanical concepts, and
the recently defined electric field intensity factor, K-E, for conducting c
racks. A four-point-bending device for fracture tests under combined electr
ical and mechanical loads serves as the experimental set-up. The measured q
uantities, force, displacement, applied voltage and crack length, are used
to evaluate the experiments. The finite element method (FEM) was used to de
termine the mechanical stress intensity factor, K-I, and the electric field
intensity factor, K-E, taking into account linear piezoelectric coupling i
n the material. A qualitative process zone model is proposed for a physical
interpretation of the Fracture curve. (C) 1998 Acta Metallurgica Inc. Publ
ished by Elsevier Science Ltd. All rights reserved.